E.2.70. Terminology: Fields relativeLatency

The relativeLatency is the latency between now and timestamp of
the last event written into the local THL. This information
gives an indication of how fresh the incoming THL information
is. On a master, it indicates whether the master is keeping up
with transactions generated on the master database. On a slave,
it indicates how up to date the THL read from the master is.

A large value can either indicate that the database is not busy,
that a large transaction is currently being read from the source
database, or from the master replicator, or that the replicator
has stalled for some reason.

An increasing relativeLatency on the
slave may indicate that the replicator may have stalled and
stopped applying changes to the dataserver.